Resp. Assessment

Question 1

Describe what is meant by the term open lung ventilation

Answer 1

Using PEEP to maintain recruitment throughout the resp. cycle

• Prevent derecruitment
• Vt is set to prevent over distention

Question 2

According to the Static volume pressure curve, where should PEEP levels be set at for open-lung ventilation?

hint

Answer 2

• Recruitment begins at above LIP (and derecruitment below the LDP)
• set peep either above the LDP/LIP.
• caution, setting above UIP could cause VILI

Question 3

What does beaking of the volume pressure curve rep?

Answer 3

The point on the volume pressure curve above the UIP and reps the overdistension of the lungs.

• The slope (compliance) decreases beyond this point.

Question 4

For VC:

1. what is the control variable
2. as lung mechanics change, what changes in response?

Answer 4

1. Volume and flows
2. Pressures

Question 5

For PC

1. what is the control variable
2. as lung mechanics change, what changes in response?

Answer 5

1. Pressure
2. Volume and flows

Question 6

For PC - Adaptive

1. what is the control variable
2. as lung mechanics change, what changes in response?

Answer 6

1. Pressure
2. Initially volumes/flow…than vent adjusts the pressure to restore the target Vt

Question 7

In PC, peak flow changes with change in R with pt. what affect does:

1. A decrease in compliance have?
2. Increase compliance have?

Answer 7

1. Decrease in C = Decrease in Vt, but not flow.
2. Increase in compliance = increase in Vt, but not peak flow

Question 8

How does compliance affect waveforms in PRVC?

Answer 8

Waveform flattens because we adjust pressure with Vt goals, meaning Pplat = PIP.

• Pmouth/tube = Resistance = PEEPset

Question 9

In pressure control, if Ti is long enough for flow to hit 0, what does it imply?

Answer 9

PIP = Pplat

• reached max inflation capacity
• alveolar pressure = vent pressure in this case

Question 10

In PRVC, how does the following affect a vent waveform?

1. Decrease in compliance
2. Increase in compliance

Answer 10

1. Decrease in compliance increases the height of waveform (more pressure needed to hit Vt)
2. Increase in compliance lowers waveform (less pressure needed to hit waveform)

**pay attention to time constants in these cases*

Question 11

In volume control (VC), how is flow kept constant on the vent considering factors like resistance?

hint think resistance formula

Answer 11

Vent increases PIP

• resistance factor/formula

Question 12

In volume control (VC), how are vent waveforms affected by resistance:

1. Increase in resistance
2. Decrease in resistance

Answer 12

1. PIP and Pplat difference gets bigger
2. PIP and Pplat difference gets smaller

Question 13

In Pressure control (PC), how are waveforms on vents affected by resistance?

Answer 13

Pressure is controlled so any changes cause the flow waveforms to move freely (up or down)

Question 14

In pressure control, how are vent waveforms affected by:

1. Increase in resistance
2. Decrease in resistance

Answer 14

1. Flow decreases
2. Flow increases

Question 15

In pressure control adaptative (PCMV) or PC adaptative, how are vent waveforms affected by resistance?

1. Increase in resistance
2. Decrease in resistance

hint, think time constants

Answer 15

1. Decrease in flow
2. Increase in flow